/*
 * Copyright (C) 2005-2011 MaNGOS <http://www.getmangos.com/>
 *
 * Copyright (C) 2008-2011 Trinity <http://www.trinitycore.org/>
 *
 * Copyright (C) 2010-2011 ProjectSkyfire <http://www.projectskyfire.org/>
 * 
 * Copyright (C) 2011 ArkCORE <http://www.arkania.net/>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#ifndef LOCKEDQUEUE_H
#define LOCKEDQUEUE_H

#include <ace/Guard_T.h>
#include <ace/Thread_Mutex.h>
#include <deque>
#include <assert.h>
#include "Debugging/Errors.h"

namespace ACE_Based {
template<class T, class LockType, typename StorageType = std::deque<T> >
class LockedQueue {
	//! Lock access to the queue.
	LockType _lock;

	//! Storage backing the queue.
	StorageType _queue;

	//! Cancellation flag.
	volatile bool _canceled;

public:

	//! Create a LockedQueue.
	LockedQueue() :
			_canceled(false) {
	}

	//! Destroy a LockedQueue.
	virtual ~LockedQueue() {
	}

	//! Adds an item to the queue.
	void add(const T& item) {
		lock();

		//ASSERT(!this->_canceled);
		// throw Cancellation_Exception();

		_queue.push_back(item);

		unlock();
	}

	//! Gets the next result in the queue, if any.
	bool next(T& result) {
		// ACE_Guard<LockType> g(this->_lock);
		ACE_GUARD_RETURN(LockType, g, this->_lock, false);

		if (_queue.empty())
			return false;

		//ASSERT (!_queue.empty() || !this->_canceled);
		// throw Cancellation_Exception();
		result = _queue.front();
		_queue.pop_front();

		return true;
	}

	template<class Checker>
	bool next(T& result, Checker& check) {
		ACE_Guard<LockType> g(this->_lock);

		if (_queue.empty())
			return false;

		result = _queue.front();
		if (!check.Process(result))
			return false;

		_queue.pop_front();
		return true;
	}

	//! Peeks at the top of the queue. Remember to unlock after use.
	T& peek() {
		lock();

		T& result = _queue.front();

		return result;
	}

	//! Cancels the queue.
	void cancel() {
		lock();

		_canceled = true;

		unlock();
	}

	//! Checks if the queue is cancelled.
	bool cancelled() {
		ACE_Guard<LockType> g(this->_lock);
		return _canceled;
	}

	//! Locks the queue for access.
	void lock() {
		this->_lock.acquire();
	}

	//! Unlocks the queue.
	void unlock() {
		this->_lock.release();
	}

	///! Calls pop_front of the queue
	void pop_front() {
		ACE_GUARD(LockType, g, this->_lock);
		_queue.pop_front();
	}

	///! Checks if we're empty or not with locks held
	bool empty() {
		ACE_GUARD_RETURN(LockType, g, this->_lock, false);
		return _queue.empty();
	}
};
}
#endif
